硫酸镁亚型盐田卤水低温冷冻结晶规律的研究

针对青海大浪滩盐湖区盐田卤水做了低温冷冻结晶规律的研究，该盐湖区为典型的硫酸镁亚型卤水，研究了其在低温冷冻时卤水的物理性质变化及析盐结晶规律。结果表明，该盐田卤水在-16~0 ℃低温冷冻时析盐顺序为MgSO4·7H2O→MgSO4·6H2O→Na2SO4·3K2SO4。通过对不同温度下的液相组分分析和固相X射线衍射分析表明，利用冷冻方式开采此卤水时，最适宜的冷冻温度应控制在-8 ℃左右。此时，该卤水组成中SO42-的质量分数低于2%，可以简化为Na+，K+，Mg2+∥Cl--H2O四元体系，以便达到开采氯化钾的工艺需求，为该盐湖卤水的综合开发利用提供理论依据。

Research on freezing crystalization behavior of magnesium sulfate subtypes brine at low temperature

The freezing crystallization law of the magnesium sulfate subtypes brine at low temperature from Dalangtan Salt Lake in Qinghai province was researched.The salt lake is a typical subtype magnesium sulfate brine lake，and the change of physical properties and the crystallization law of salts during the freezing crystallization at low temperature were also investigated.Results showed that the order of crystallization behavior was：MgSO4·7H2O→MgSO4·6H2O→Na2SO4·3K2SO4 when low freezing brine from 0 ℃ to-16 ℃.Liquid phase composition analysis and solid phase X-ray diffraction analysis showed that the most suitable freezing temperature should be controlled at about-8 ℃.At this point，SO42- mass fraction was lower than 2%，the brine could be simplified as Na+，K+，Mg2+∥Cl-H2O quaternary system and achieved the goal of exploitation of potassium chloride.These data provided a theoretical basis for the comprehensive exploitation and utilization of the brine of Dalangtan Salt Lake.